Louisville Mayor Ashley Stolzmann wants to ban natural gas hookups in new commercial buildings. “We’ve been talking about it for long enough,” Stolzmann said. "If we’d done it faster, we would have been first" in Colorado. Courtesy of Ashley Stolzmann

This summer, Crested Butte became the first municipality in Colorado to ban natural gas in new buildings. Other than cooking in commercial kitchens, everything in the mountain town’s new structures must be achieved electrically. If it had been up to Ashley Stolzmann, however, Boulder’s neighbor would have taken gold.

“We’ve been talking about it for long enough,” Stolzmann, Louisville’s mayor, said. “If we’d done it faster, we would have been first.”

Berkeley, California was the first U.S. city to ban natural gas hookups in new buildings. Between Berkeley’s 2019 decision and today, some 60 California cities and counties have followed suit, as have several cities in other states, including New York City. Climate change is the impetus. Carbon dioxide emissions must fall to zero as early as 2050, if we hope to keep warming within safe margins. Rapid cuts in non-CO2 drivers of warming must also be made, including methane — also known as natural gas. 

“We are facing a climate emergency,” Stolzmann said. “And a lot of what we see in response is not rising to the occasion to reduce our emissions in a way that’s really going to help our generation and the next.”

On Sept. 27, 2022, Louisville City Council held a special meeting to discuss options for updating the city’s commercial energy code. Honing in on the language of such a code, however, can take more than a few meetings.

City staff and some engineering groups, who act as the city’s consultants, presented options for paths forward. Some potential codes were less aggressive, encouraging all-electric construction while allowing for “flexibility with fuel choice and energy use reduction methods.” Others were more ambitious: net-zero emissions, solar generation on site, and no natural gas to speak of. Or at least almost none. Exceptions would be possible.

Stolzmann pushed the council towards the latter.

“The longer we defer and delay on taking climate action, the worse it gets for future generations,” Stolzmann told the council. “When people say ‘I care about the environment but I’m going to vote against everything,’ I just hear the tragedy of the commons.”

Natural gas emissions, including from buildings’ natural gas hookups, accounted for 32% of U.S. methane emissions in 2020. Though methane represented 10% of greenhouse gas emissions — compared with carbon dioxide’s 79% — methane heats the planet with vigor. Over a 20 -year timescale, one ton of methane will warm the earth 56 times more than the same amount of carbon dioxide.

Talks about the potential ordinance’s language will continue over the coming months. A vote could come before year’s end.

Avoid retrofitting, for now

Stolzmann told Boulder Reporting Lab that the discussion for improving Louisville’s commercial building code began when the city examined how it could reduce transportation and building emissions, both of which are high and both without good strategies for reduction. (According to the EPA’s website, residential and commercial emissions accounted for 13% of U.S. emissions in 2020.) The best first step, Stolzmann realized, was to stop installing gas hookups in new builds, as “retrofitting is really hard.”

Retrofitting means updating a building with heating units and appliances that don’t use gas. That can entail replacing a stove and oven, a water heater and a furnace. In Boulder, BRL reported on a resident retrofitting a townhome. The cost ran over $30,000. A commercial building would presumably be much more expensive.

“Building it right the first time is so much more cost effective,” Stolzmann said.

For now, for Stolzmann, it’s about just taking a step. Her first push is banning natural gas hookups in new commercial buildings. Emphasis on new, because, as Stolzmann said, people are already misunderstanding her.

“I’ve gotten probably 30 emails saying, ‘Hey, this building downtown can’t afford to retrofit right now, don’t do this,’” she said. “And I’ll write back that this [ordinance] has nothing to do with retrofitting. Then [people] say, ‘Yes it does, that’s what I heard.’”

Stolzmann said that while she “hasn’t met anyone who’s passionate about methane,” she does hear from people who are concerned about the cost and ability of electric appliances to perform. The performance fear, Stolzmann said, is hedged in electric technology of the 70s and 80s.

“People think it’s their grandmother’s electric heater,” she said. “It’s just not.”

Modern heat pumps are more efficient than electric heaters of old, though heat pumps aren’t new. Heat pump technology is already used in many air conditioning and refrigeration units today. For heat, the air just runs in the opposite direction. In the summer, when your A/C kicks on, it moves hot air from inside your home to dispel it outside. Heat pumps, when used in winter, take hot air from outside and push it in. 

But the colder it is, the harder (air-source) heat pumps have to work to find heat outside, therefore using more electricity. This is where talk about the electric grid comes in. Or, as a citizen said in response to Crested Butte’s ban, “We don’t have the infrastructure in place to do this.”

Should every home in a town suddenly electrify all the systems natural gas previously handled, demands on the electric grid could spike over what that electric grid — or infrastructure — is able to deliver. But not every home in Louisville or Crested Butte will suddenly be 100% electric. It’s a process. By starting with just new buildings, the grid has time to evolve.

On the U.S. Department of Energy website, there’s a 2019 report on how the grid would handle an increase in electric vehicles. Just as with electrifying buildings, there’s worry about what would happen if every house suddenly started charging electric vehicles each night. But a conclusion reached in the paper says, “Based on historical growth rates, sufficient energy generation and generation capacity is expected to be available to support a growing EV fleet as it evolves over time, even with high EV market growth.” 

Not everyone will switch to electric vehicles all at once. The grid will have time to evolve. It’s a process.

The same mindset could apply to electrifying buildings. Start with new buildings, then take the next step.

“If we can get everyone on track with no gas in new builds,” Stolzmann said, “then we can really get started on those retrofits, which will be much harder.”

Ithaca, New York, slightly bigger than Louisville, recently voted to completely decarbonize its new and existing buildings by 2030, retrofits included. Stolzmann said one step Ithaca is taking to reduce transition costs for residents is bulk purchasing heat pumps so savings can be passed on to individuals. This practice shows the advantages a smaller town, like Louisville, has when making such a change.

“By having a small enough community, you can hear the direct concerns and try to address them,” she said.

Concern for business, hard on hospitals

One concern for the potential ordinance was the effect it would have on businesses. “At the end of the day we need to balance our sustainability goals, which I very much support, with the economic vitality and sustainability of our city,” said Councilmember Dennis Maloney at the council meeting.

Mark Oberholzer, owner of Tilt Pinball in Louisville, also spoke up about the ordinance potentially inciting an exodus from Louisville. “[Surrounding communities] are already soliciting our businesses to relocate,” he said. “Having Louisville make it harder for businesses to operate here will provide them a push to relocate elsewhere.”

And Councilmember Chris Leh told Boulder Reporting Lab that certain life-saving technologies still need gas, at least for now. 

“Hospitals need to have back up energy supplies,” Leh said. “You need to have generators to keep people alive. And the generators that are available and feasible to use are gas generated.”

Should such a ban go into effect, it’s likely certain exceptions would be in place, like those in Crested Butte.

Local dissenters are not alone, however. With the backing of gas utilities and industry groups, many states have passed preemptive legislation to prevent cities within their boundaries from ever considering such ordinances. Some in Colorado tried, but failed.

What about Boulder?

Where does Boulder stand on all this?

“New construction represents a very small fraction of the buildings in Boulder in the first place,” said Carolyn Elam, Energy Systems Senior Manager for the City of Boulder. “Executing a [natural gas in new buildings] ban, how much are we actually moving the needle?”

Elam said that Boulder has many research and medical facilities – echoing some of Leh’s concerns – that rely on equipment that doesn’t have an electric counterpart yet, or at least not one that’s financially feasible.

“There’s not technology that will replace all gas applications in buildings,” Elam said.

Elam added that Boulder is biding its time to see what happens to lawsuits in California, where restaurant groups are suing for access to gas. Crested Butte’s ban allows for gas in commercial kitchens.

“So far, we’ve focused our efforts on voluntary programs and education for electrification,” Elam said. “We encourage all electric construction and provide more of an incentive-based strategy for achieving that.”

Elam said moving forward, Boulder would probably pursue updates to the building code that specify which aspects of a home or commercial building must be electric, then let the building owner decide whether gas is also needed.

“Boulder has one of the most aggressive building codes in the country and we try not to push it so far such that we’re just shifting the problem somewhere else,” Elam said. “Meaning, instead of building in Boulder to a highly efficient standard, [potential residents] elect to build somewhere else in Colorado to a lower standard.”

Tim Drugan is the climate and environment reporter for Boulder Reporting Lab, covering wildfires, water and other climate-related issues for Boulder with a focus on explanatory and solutions journalism. He also is the lead writer of BRL Today, our morning newsletter. Tim grew up in New Hampshire and graduated from UNH with a degree in English/Journalism. Email: tim@boulderreportinglab.org.

Join the Conversation


  1. Your headline, “Louisville Seeks to Become…” is an inaccurate, misleading way to characterize what’s happening. It’s Louisville’s Mayor who continues to inflict a long list of environmental edicts upon Louisville’s residents and businesses. These edicts will continue to erode the vitality of Louisville.
    Louisville passed regulation to require a variety of “energy and safety” features on je home builds one month before the devastating Dec 28 fire, with a 3 to 2 City Council vote – based in part on the erroneous estimate from an unnamed “expert” who said the incremental cost for new energy and safety requirements would be “about $20,000” for the average new home in Louisville. Local contractors subsequently indicated the incremental cost would likely be $80,000 or more. Those residential stipulations also applied to new commercial construction, making such new builds much more costly.
    What is happening in Louisville is a shameful disaster; we’ve lost Kohl’s, Sam’s Club (many years ago), Lowe’s, Carrabba’s, Papa Murphy’s, Chili’s, Outback Steakhouse, Alphalpha’s, Hobby Lobby, and several other retail stores- and Medtronic will soon vacate Louisville as well.
    The controllable part of this disappointing exodus is maintaining the status quo is Louisville – which allowed it to be named the best small town in America by Money magazine- not by saddling the populace, existing businesses and potential new residents and businesses with extremely expensive, onerous and sometimes cost-prohibitive requirements for building new homes and operating businesses here.
    Louisville is on a sad decline that has been caused by the extreme measures taken by the Mayor and the City Council that she has obviously influenced.
    She and City Council are to blame for what is happening right now, and where Louisville is headed. It’s not pretty now and it’s getting uglier.
    So please do not characterize Louisville as a whole who wants these onerous building requirements. It’s the Mayor, City Council, and some local residents who are blind the the unfortunate unanticipated consequence; Louisville in utter decline.
    Marc Miller
    Louisville resident since 1987

  2. Thank you to Tim Drugan and to Boulder Reporting Lab for your in-depth summary of Louisville’s efforts to reduce the city’s carbon footprint.

    I have to respond to Marc Miller’s reaction to this article. He seems to have made a classic error, widely recognized in scientific circles: mistaking “correlation” for “causation”.

    The stores and restaurants in Louisville he mentioned have indeed closed. Louisville is indeed working on regulations intended to improve energy efficiencies and reduce carbon emissions. These happened over roughly the same time frame–that’s “correlation”. Mr. Miller implies Louisville’s actions “caused” the closures–that would be “causation”. In place of this rush to judgement, here are some reasonable alternative explanations:

    Could Lowe’s have closed because of competition from Home Depot and the opportunities available with its new, state-of-the-art store in Lafayette, convenient to ongoing growth in east Boulder County? Could Chili’s, Outback, and Papa Murphy’s have closed because of lack of business during the Covid-19 epidemic? Could Hobby Lobby have closed because of the ease of e-commerce? Could Medtronic “soon vacate Louisville” because the residents of Louisville made their choice in voting to not allow a large new development (Redtail Ridge) with attendant traffic, noise and congestion?

    Mr. Miller may not have recognized that Climate Change is upon us and accelerating. Many New York Times articles in 2022 have informed us: “Climate Change Added to Texas Flooding, Study Finds” (Aug. 26); “Study Concludes Greenhouse Emissions Made Summer Drier and Hotter” (Oct. 6). And from Boulder’s Daily Camera: “NCAR: Water Instability Linked to Climate Change” (July 1).

    We all need to come together and accept some inconveniences (and, yes, some financial impacts) to do our parts to reduce future consequences of climate change that will otherwise be devastating. Remember the Marshall Fire? Businesses are willing to meet these challenges.

    Thank you, Ashley Stolzmann, as Louisville’s mayor, for being a leader on this existential issue. Your priorities are essential for addressing our 21st century’s challenges.

    John Cowley
    Boulder County resident since 1980

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